Hanger later said he couldn't look back on the days after his amputation "without a shudder," according to Hanger Inc., the company he went on to create.
"No one can know what such a loss means unless he has suffered a similar catastrophe," he said. "In the twinkling of an eye, life's fondest hopes seemed dead. I was the prey of despair. What could the world hold for a maimed, crippled man?"
In August 1861, Hanger was released from the Union's control in a prisoner exchange and returned home to his family in Virginia. He was using the standard prosthetic at the time - a roughly constructed peg leg.
When he arrived home, he asked his family for solitude and spent weeks alone in his bedroom.
They assumed he was coping with his amputation. In fact, Hanger spent the time working to develop a better leg.
And he did - his new prosthetic leg was more comfortable and allowed for a greater range of motion than the standard-issue prosthetics of the time.
"He kept working to improve the leg until he got it developed so it was fully functional," Robison said.
Hanger soon secured two patents for his prosthetics from the Confederate government and began working with the army to make artificial limbs for other soldiers who had their legs or arms amputated. In 1891, Hanger was granted a U.S. patent.
By the time of World War I, Hanger was so far ahead in the business of making prosthetics that he moved his business to Washington, D.C., to produce artificial limbs for the federal government again - this time for World War I veterans.
The company is still running strong. Today, Hanger is a national, publicly traded company with more than 4,000 employees and branches in Atlanta, Philadelphia, Pittsburgh, St. Louis, London and Paris. And that company, Hanger's legacy, has created a slew of new and innovative limbs in the years since Hanger was first wounded in the Civil War.